Buggy code:
@ SuppressWarnings ( "deprecation" ) public class ExtensionRegistry { private final ProcessType processType ; private SubsystemXmlWriterRegistry writerRegistry ; private volatile PathManager pathManager ; private volatile ManagementResourceRegistration profileRegistration ; private volatile ManagementResourceRegistration deploymentsRegistration ; private final ConcurrentMap < String , ExtensionRegistry . ExtensionInfo > extensions = new ConcurrentHashMap < String , ExtensionRegistry . ExtensionInfo > ( ) ; private final ConcurrentMap < String , String > reverseMap = new ConcurrentHashMap < String , String > ( ) ; private final RunningModeControl runningModeControl ; private boolean unnamedMerged ; private final ConcurrentHashMap < String , SubsystemInformation > subsystemsInfo = new ConcurrentHashMap < String , SubsystemInformation > ( ) ; private volatile TransformerRegistry transformerRegistry = Factory . create ( this ) ; public ExtensionRegistry ( ProcessType processType , RunningModeControl runningModeControl ) { } public ProcessType getProcessType ( ) { } public void setWriterRegistry ( final SubsystemXmlWriterRegistry writerRegistry ) { } public void setPathManager ( final PathManager pathManager ) { } public void setSubsystemParentResourceRegistrations ( ManagementResourceRegistration profileResourceRegistration , ManagementResourceRegistration deploymentsResourceRegistration ) { } public ManagementResourceRegistration getProfileRegistration ( ) { } public SubsystemInformation getSubsystemInfo ( final String name ) { } public Set < String > getExtensionModuleNames ( ) { } public Map < String , SubsystemInformation > getAvailableSubsystems ( String moduleName ) { } public ExtensionParsingContext getExtensionParsingContext ( final String moduleName , final XMLMapper xmlMapper ) { } public ExtensionContext getExtensionContext ( final String moduleName , boolean isMasterDomainController ) { } @ Deprecated public ExtensionContext getExtensionContext ( final String moduleName ) { } public Set < String > getUnnamedNamespaces ( final String moduleName ) { } public Set < ProfileParsingCompletionHandler > getProfileParsingCompletionHandlers ( ) { } public void removeExtension ( Resource rootResource , String moduleName ) throws IllegalStateException { } public void clear ( ) { } public void recordSubsystemVersions ( String moduleName , ModelNode subsystems ) { final Map < String , SubsystemInformation > subsystemsInfo = getAvailableSubsystems ( moduleName ) ; if ( ( subsystemsInfo != null ) && ( ! ( subsystemsInfo . isEmpty ( ) ) ) ) { for ( final Map . Entry < String , SubsystemInformation > entry : subsystemsInfo . entrySet ( ) ) { <START_BUG> subsystems . add ( entry . getKey ( ) , ( ( ( entry . getValue ( ) . getManagementInterfaceMajorVersion ( ) ) + "." ) + ( entry . getValue ( ) . getManagementInterfaceMinorVersion ( ) ) ) ) ; <END_BUG> } } } private ExtensionRegistry . ExtensionInfo getExtensionInfo ( final String extensionModuleName ) { } private void checkNewSubystem ( final String extensionModuleName , final String subsystemName ) { } private void mergeUnnamedParsers ( ) { } public TransformerRegistry getTransformerRegistry ( ) { } private class ExtensionParsingContextImpl implements ExtensionParsingContext { private final ExtensionRegistry . ExtensionInfo extension ; private ExtensionParsingContextImpl ( String extensionName , XMLMapper xmlMapper ) { } @ Override public ProcessType getProcessType ( ) { } @ Override @ SuppressWarnings ( "deprecation" ) public void setSubsystemXmlMapping ( String namespaceUri , XMLElementReader < List < ModelNode > > reader ) { } @ Override public void setSubsystemXmlMapping ( String subsystemName , String namespaceUri , XMLElementReader < List < ModelNode > > reader ) { } @ Override @ SuppressWarnings ( "deprecation" ) public void setDeploymentXmlMapping ( String namespaceUri , XMLElementReader < ModelNode > reader ) { } @ Override @ SuppressWarnings ( "deprecation" ) public void setDeploymentXmlMapping ( String subsystemName , String namespaceUri , XMLElementReader < ModelNode > reader ) { } @ Override public void setProfileParsingCompletionHandler ( ProfileParsingCompletionHandler handler ) { } } public class ExtensionContextImpl implements ExtensionContext { private final ExtensionRegistry . ExtensionInfo extension ; private final PathManager pathManager ; private final boolean registerTransformers ; private ExtensionContextImpl ( String extensionName , PathManager pathManager , boolean registerTransformers ) { } @ Override public SubsystemRegistration registerSubsystem ( String name , int majorVersion , int minorVersion ) throws IllegalArgumentException , IllegalStateException { } @ Override public SubsystemRegistration registerSubsystem ( String name , int majorVersion , int minorVersion , int microVersion ) { } @ Override public SubsystemRegistration registerSubsystem ( String name , int majorVersion , int minorVersion , int microVersion , boolean deprecated ) { } @ Override public ProcessType getProcessType ( ) { } @ Override public RunningMode getRunningMode ( ) { } @ Override public boolean isRuntimeOnlyRegistrationValid ( ) { } @ Override public PathManager getPathManager ( ) { } @ Override public boolean isRegisterTransformers ( ) { } } private class SubsystemInformationImpl implements SubsystemInformation { private Integer majorVersion ; private Integer minorVersion ; private Integer microVersion ; private boolean deprecated = false ; private final List < String > parsingNamespaces = new ArrayList < String > ( ) ; @ Override public List < String > getXMLNamespaces ( ) { } void addParsingNamespace ( final String namespace ) { } @ Override public Integer getManagementInterfaceMajorVersion ( ) { } private void setMajorVersion ( Integer majorVersion ) { } @ Override public Integer getManagementInterfaceMinorVersion ( ) { } private void setMinorVersion ( Integer minorVersion ) { } @ Override public Integer getManagementInterfaceMicroVersion ( ) { } private void setMicroVersion ( Integer microVersion ) { } public boolean isDeprecated ( ) { } private void setDeprecated ( boolean deprecated ) { } } public class SubsystemRegistrationImpl implements SubsystemRegistration { private final String name ; private SubsystemRegistrationImpl ( String name ) { } @ Override @ SuppressWarnings ( "deprecation" ) public ManagementResourceRegistration registerSubsystemModel ( final DescriptionProvider descriptionProvider ) { } @ Override public ManagementResourceRegistration registerSubsystemModel ( ResourceDefinition resourceDefinition ) { } @ Override @ SuppressWarnings ( "deprecation" ) public ManagementResourceRegistration registerDeploymentModel ( final DescriptionProvider descriptionProvider ) { } @ Override public ManagementResourceRegistration registerDeploymentModel ( ResourceDefinition resourceDefinition ) { } @ Override public void registerXMLElementWriter ( XMLElementWriter < SubsystemMarshallingContext > writer ) { } @ Override public TransformersSubRegistration registerModelTransformers ( final ModelVersionRange range , final ResourceTransformer subsystemTransformer ) { } @ Override public TransformersSubRegistration registerModelTransformers ( ModelVersionRange version , ResourceTransformer resourceTransformer , OperationTransformer operationTransformer ) { } @ Override public TransformersSubRegistration registerModelTransformers ( ModelVersionRange version , CombinedTransformer combinedTransformer ) { }

Fix:
subsystems . add ( entry . getKey ( ) , ( ( ( entry . getValue ( ) . getManagementInterfaceMajorVersion ( ) ) + "." ) + ( entry . getValue ( ) . getManagementInterfaceMicroVersion ( ) ) ) ) ;